Aneurysmal segments of the aorta are usually replaced because they are prone to rupture. Also, patients who suffer from senile aortic valve stenosis often require aortic valve replacement (AVR), and in many of those patients, concomitant aneurysmal disease requires the replacement of all or a portion of the ascending aorta.
With age, the aorta tends to dilate and stiffen. A stiffened aorta conducts a pressure wave (incident wave) faster, leading to a faster return pressure wave (reflected wave). This faster reflected wave may have deleterious effects: it can widen pulse pressure (the difference between systolic and diastolic pressure) and can give a higher systolic pressure due to summation with the incident wave. Indeed, wave reflections were observed to be responsible for an increase of about 25% in pulse pressure between the ages of 30 and 60 years (Kelley et al., 1989, Circulation 80:1652-1659). The consequences of the higher systolic pressures and widened pulse pressures due to aorta stiffening may include increases in heart strain and cognitive dysfunction (Scuteri, 2013, Intern Journ Cardiol 169:371-377; Merillon, 2014, Arch Cardiovas Disease 107:554-562). Yet, stiffness and non-compliance of the aorta is not a typical indication for replacement.
The present invention features an expansible cardiovascular graft system for replacing a portion of a vessel, e.g., the aorta, e.g., all or a portion of the ascending aorta. The expansible cardiovascular graft system allows for gradual expansion (e.g., in systole) and recoil (e.g., in diastole). The expansible cardiovascular graft system is not limited to use in the aorta.
The present invention also features methods of treating cardiovascular conditions such as aneurysmal disease by replacing a portion of the aorta (or other appropriate vessel) with the cardiovascular graft system of the present invention. The present invention is not limited to treating aneurysmal vessels. For example, in some embodiments, the graft system of the present invention is used to replace a portion of (or all of) a stiffened vessel, e.g., a stiffened portion of the aorta. This may or may not be subsequent to AVR.
Non-limiting examples of replaceable cardiovascular segments include the infrarenal aorta, the descending thoracic aorta, and the ascending thoracic aorta. The system of the present invention is not limited to vessel replacement; for example, in some embodiments, the system of the present invention is incorporated into a catheter system. In some embodiments, the system of the present invention is used as an endovascular graft. In this example, remaining vascular tissue (e.g., aneurysmal tissue) may create a protected space around the graft, which may delay potential encasement in scar tissue.
Any feature or combination of features described herein are included within the scope of the present invention provided that the features included in any such combination are not mutually inconsistent as will be apparent from the context, this specification, and the knowledge of one of ordinary skill in the art. Additional advantages and aspects of the present invention are apparent in the following detailed description and claims.